Nanocrystalline SnO2 thin films with the cassiterite structure and grains 5-10 nm in size were deposited from precipitating aqueous solutions of SnCl4 x 5H(2)O and HCl at 80 degrees C. The substrates were single-crystal {100} silicon wafers, either with or without sulfonate-functionalized self-assembled monolayer (SAM) coatings. Films, 60-70 nm thick, were obtained in 12 h from a medium of 2 mM SnCl4/0.4 M HCl. These films grew at a rate of approximately 9 nm h(-1) during the first 4 h. Thicker films, 160 nm thick, containing cassiterite grains 5-10 nm in size were obtained by continuously flowing a solution of 2 mM SnCl4/0.2 M HCl past the substrates. The as-deposited films were uniform and adherent. They contained similar to 2-3 at.% Cl and excess oxygen (2 < O/Sn < 3). A detailed X-ray photoelectron spectroscopy (XPS) analysis of the oxygen content of the films indicates that the additional oxygen may be present in an amorphous tin oxyhydroxide phase.